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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2013 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_SYNC_H
#define BITCOIN_SYNC_H
#include "threadsafety.h"
#include <boost/thread/condition_variable.hpp>
#include <boost/thread/locks.hpp>
#include <boost/thread/mutex.hpp>
#include <boost/thread/recursive_mutex.hpp>
////////////////////////////////////////////////
// //
// THE SIMPLE DEFINITON, EXCLUDING DEBUG CODE //
// //
////////////////////////////////////////////////
/*
CCriticalSection mutex;
boost::recursive_mutex mutex;
LOCK(mutex);
boost::unique_lock<boost::recursive_mutex> criticalblock(mutex);
LOCK2(mutex1, mutex2);
boost::unique_lock<boost::recursive_mutex> criticalblock1(mutex1);
boost::unique_lock<boost::recursive_mutex> criticalblock2(mutex2);
TRY_LOCK(mutex, name);
boost::unique_lock<boost::recursive_mutex> name(mutex, boost::try_to_lock_t);
ENTER_CRITICAL_SECTION(mutex); // no RAII
mutex.lock();
LEAVE_CRITICAL_SECTION(mutex); // no RAII
mutex.unlock();
*/
///////////////////////////////
// //
// THE ACTUAL IMPLEMENTATION //
// //
///////////////////////////////
// Template mixin that adds -Wthread-safety locking annotations to a
// subset of the mutex API.
template <typename PARENT>
class LOCKABLE AnnotatedMixin : public PARENT
{
public:
void lock() EXCLUSIVE_LOCK_FUNCTION()
{
PARENT::lock();
}
void unlock() UNLOCK_FUNCTION()
{
PARENT::unlock();
}
bool try_lock() EXCLUSIVE_TRYLOCK_FUNCTION(true)
{
return PARENT::try_lock();
}
};
/** Wrapped boost mutex: supports recursive locking, but no waiting */
// TODO: We should move away from using the recursive lock by default.
typedef AnnotatedMixin<boost::recursive_mutex> CCriticalSection;
/** Wrapped boost mutex: supports waiting but not recursive locking */
typedef AnnotatedMixin<boost::mutex> CWaitableCriticalSection;
#ifdef DEBUG_LOCKORDER
void EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry = false);
void LeaveCritical();
std::string LocksHeld();
void AssertLockHeldInternal(const char* pszName, const char* pszFile, int nLine, void *cs);
#else
void static inline EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry = false) {}
void static inline LeaveCritical() {}
void static inline AssertLockHeldInternal(const char* pszName, const char* pszFile, int nLine, void *cs) {}
#endif
#define AssertLockHeld(cs) AssertLockHeldInternal(#cs, __FILE__, __LINE__, &cs)
#ifdef DEBUG_LOCKCONTENTION
void PrintLockContention(const char* pszName, const char* pszFile, int nLine);
#endif
/** Wrapper around boost::unique_lock<Mutex> */
template<typename Mutex>
class CMutexLock
{
private:
boost::unique_lock<Mutex> lock;
void Enter(const char* pszName, const char* pszFile, int nLine)
{
EnterCritical(pszName, pszFile, nLine, (void*)(lock.mutex()));
#ifdef DEBUG_LOCKCONTENTION
if (!lock.try_lock())
{
PrintLockContention(pszName, pszFile, nLine);
#endif
lock.lock();
#ifdef DEBUG_LOCKCONTENTION
}
#endif
}
bool TryEnter(const char* pszName, const char* pszFile, int nLine)
{
EnterCritical(pszName, pszFile, nLine, (void*)(lock.mutex()), true);
lock.try_lock();
if (!lock.owns_lock())
LeaveCritical();
return lock.owns_lock();
}
public:
CMutexLock(Mutex& mutexIn, const char* pszName, const char* pszFile, int nLine, bool fTry = false) : lock(mutexIn, boost::defer_lock)
{
if (fTry)
TryEnter(pszName, pszFile, nLine);
else
Enter(pszName, pszFile, nLine);
}
~CMutexLock()
{
if (lock.owns_lock())
LeaveCritical();
}
operator bool()
{
return lock.owns_lock();
}
};
typedef CMutexLock<CCriticalSection> CCriticalBlock;
#define LOCK(cs) CCriticalBlock criticalblock(cs, #cs, __FILE__, __LINE__)
#define LOCK2(cs1,cs2) CCriticalBlock criticalblock1(cs1, #cs1, __FILE__, __LINE__),criticalblock2(cs2, #cs2, __FILE__, __LINE__)
#define TRY_LOCK(cs,name) CCriticalBlock name(cs, #cs, __FILE__, __LINE__, true)
#define ENTER_CRITICAL_SECTION(cs) \
{ \
EnterCritical(#cs, __FILE__, __LINE__, (void*)(&cs)); \
(cs).lock(); \
}
#define LEAVE_CRITICAL_SECTION(cs) \
{ \
(cs).unlock(); \
LeaveCritical(); \
}
class CSemaphore
{
private:
boost::condition_variable condition;
boost::mutex mutex;
int value;
public:
CSemaphore(int init) : value(init) {}
void wait() {
boost::unique_lock<boost::mutex> lock(mutex);
while (value < 1) {
condition.wait(lock);
}
value--;
}
bool try_wait() {
boost::unique_lock<boost::mutex> lock(mutex);
if (value < 1)
return false;
value--;
return true;
}
void post() {
{
boost::unique_lock<boost::mutex> lock(mutex);
value++;
}
condition.notify_one();
}
};
/** RAII-style semaphore lock */
class CSemaphoreGrant
{
private:
CSemaphore *sem;
bool fHaveGrant;
public:
void Acquire() {
if (fHaveGrant)
return;
sem->wait();
fHaveGrant = true;
}
void Release() {
if (!fHaveGrant)
return;
sem->post();
fHaveGrant = false;
}
bool TryAcquire() {
if (!fHaveGrant && sem->try_wait())
fHaveGrant = true;
return fHaveGrant;
}
void MoveTo(CSemaphoreGrant &grant) {
grant.Release();
grant.sem = sem;
grant.fHaveGrant = fHaveGrant;
sem = NULL;
fHaveGrant = false;
}
CSemaphoreGrant() : sem(NULL), fHaveGrant(false) {}
CSemaphoreGrant(CSemaphore &sema, bool fTry = false) : sem(&sema), fHaveGrant(false) {
if (fTry)
TryAcquire();
else
Acquire();
}
~CSemaphoreGrant() {
Release();
}
operator bool() {
return fHaveGrant;
}
};
#endif

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